enwaecphysics2006

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1. Which of the following phenomena causes capillarity of liquids in tubes of narrow bore? Viscosity Surface tension Osmosis Brownian motion 2. Which of the following physical quantities are derived? Area Thrust Pressure Mass I, II, III and IV I, II and III only I, II and IV only I and III only 3. A block of volume 3×105m3 and density 2.5 ×103kg m-3 is suspended from a spring balance with □(2/3) of its volume immersed in a liquid of density 900 kg m-3. Determine the reading of the spring balance. [g= 10 ms-2] 0.18 N 0.57 N 0.75 N 0.93 N 4. A solid will float in a liquid if its Density is less than that of the liquid Mass is equal to that of the liquid Density is greater than that of the liquid Mass is less than that of the liquid 5. An object is said to undergo oscillatory motion when it moves In an erratic manner To and for about a fixed point In a circular path Along a continuous path from the starting point 6. A moving car of mass 800 kg experiences a frictional force of 200 N. If it accelerates 2 ms-2, calculate the magnitude of the force applied to the car. 600 N 1000 N 1600 N 1800 N 7. A body is rotating in a horizontal circle of radius 2.5 m with an angular speed of 5 rad s-1. Calculate the magnitude of the radial acceleration of the body 62.50 ms-2 31.25 ms-2 12.50 ms-2 10.00 ms-2 8. Uniform speed occurs when there is equal change of Distance in equal times Displacement in equal times Velocity in equal times Acceleration in equal times 9. A car accelerates uniformly form rest at 5ms-2. Determine its speed after 10s. 50.0 ms-1 25.0 ms-1 2.0 ms-1 0.5 ms-1 10. The diagram above shows the speed-time graph of a car. If the car covered a total distance of 600ImI in 25 s, calculate its maximum speed. 30 ms-1 25 ms-1 20 ms-1 15 ms-1

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11. Which of the following quantities is a vector? Speed Distance Energy momentum 12. Determine the magnitude of P in the diagram above. 16 N 20 N 32 N 40 N 13. Which of the following statements about simple harmonic motion is correct? The Total mechanical energy is always conserved Linear acceleration is directed to any variable point Linear acceleration varies inversely with displacement Period of oscillation varies linearly as acceleration due to gravity 14. A force acting on a body causes a change in the momentum of the body from 12 kg ms-1 to 16 kg ms-1 in 0.25 s. Calculate the magnitude of the impulse. 28.0 Ns 20.0 Ns 4.0 Ns 0.8 Ns 15. Which of the following sources of energy is renewable? Petroleum Charcoal Hydro Nuclear 16. A stone of mass 2.0 kg is thrown vertically upwards with a velocity of 20.0 ms-1, calculate the initial kinetic energy of the stone. 200 J 400 J 800 J 1600 J 17. Which of the following statements about the mouthpiece of a telephone is correct? It converts sound energy into Acoustic energy Mechanical energy Electrical energy Heat energy 18. The potential energy in an elastic string of force constant k which has been extended by x metres is expresses as 1/2k□2 k□2 1/2k□ k□ 19. The engine of a train produces a force of 3000N when moving at 30 ms-1. Calculate the power of the engine. 1.00 × 102W 3.00×104W 9.00 × 104W 3.00 × 105W 20. The velocity ratio of an inclined plane, inclined at an angle θ to the horizontal can be expressed as (sin θ)-1 Sin θ (cos θ)-1 Cos θ

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21. A block and tackle system has six pulleys. A force of 50 N applied to it lifts a load of weight W. If the efficiency of the system is 40%, calculate W. 300 N 200 N 140 N 120 N 22. The sagging of overhead electrical cables is the consequence of Linear expansivity Superficial expansivity Cubic expansivity Conductivity 23. The silvered surface in a vacuum flask reduces heat loss due to Conduction Convection radiation evaporation 24. How long will it take to heat 3 kg of water from 28℃ to 88℃ in an electric kettle taking 6A from a 220V supply? [Specific heat capacity of water = 4180 J kg-1K-1] 120 s 570 s 600 s 836 s 25. The amount of energy required to change a kilogram of ice block into water without a change in temperature is Heat capacity of ice Specific heat capacity Specific latent heat of vaporization Specific latent heat of fusion of ice 26. A quantity of steam at 100℃ condenses to water at the same temperature by releasing 6.9 × 104J of energy. Calculate the mass of the condensed steam. [Specific latent heat of vaporization of water = 2.3 ×106J kg-1] 3.0×10-1kg 3.0×10-2kg 3.0×10-3kg 3.0×10-4kg 27. The temperature of a liquid falls after some of it has evaporated because The liquid left is smaller in volume and the breeze easily cools it The more energetic molecules have escaped into the atmosphere The liquid left has latent heat After evaporation impurities are left behind 28. The S.I. units of frequency, period and amplitude of a wave are respectively Hertz, second and centimeter Second, metre and hertz Metre, hertz and second Hertz, second and metre 29. A note of frequency 2000 Hz has a velocity 400 ms-1. Calculate the wavelength of the note 5.0 m 2.0 m 0.5 m 0.2 m 30. The eclipse of the moon occurs when the Moon comes exactly between the earth and the sun Earth comes exactly between the moon and the sun Sun comes exactly between the earth and the moon Moon reflects all rays from the sun onto the earth

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31. Which of the following observations cannot be explained using rectilinear propagation of light? Production of images by a pinhole camera Production of real images of objects by lenses Formation of annular eclipse Diffraction patterns of light 32. The distance between the successive crests of a wave travelling at 20 ms-1 is 25 cm. Calculate the frequency of the wave 0.8 Hz 5.0 Hz 50.0 Hz 80.0 Hz 33. A ray form a fixed object is incident on a plane mirror at an angle of 20°. If the mirror is rotated through 30°, by how many degree would the reflected ray rotate? 60° 50° 40° 30° 34. Which of the following distance s is usually adjustable in the camera? The distance between the Lens and the film Diaphragm and the shutter Shutter and the film Diaphragm and the film 35. A travelling microscope is focused on a mark on a table. If a glass block of thickness 18.0 cm is placed on the mark, by how many centimetres will the microscope be moved upwards so as to focus the mark once again? [Refractive index of light =1.5] 27 cm 24 cm 9 cm 6 cm 36. In which of the following media would sound wave travel faster? Wood Water Iron Mercury 37. Which of the following actions is necessary in order to tune a string to produce a note of an octave higher than its fundamental? Doubling the length of the string Reducing the tension by half Reducing the mass per unit length Increasing the tension four times 38. The acceleration due to gravity may be defined as the force Of attraction of the sun on the earth With which the earth revolves round the sun With which the earth attracts one-kilogram mass Of the moon on the earth 39. An electron of mass m and charge □ enters a uniform electric field between two metal plates P and Q separated by a distance d. P is maintained at a potential V while q is earthed. Determine an expression for the magnitude of the acceleration of electron through the field. eV/md d/meV md/eV e/Vmd 40. Which of the following factors does not affect the capacitance of a parallel plate conductor? Area of the plates Nature of the surface of the plates Distance of separation between the plates Nature of the insulating material between the plates

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41. The equivalent capacitance of a 3μF capacitor and a 6μF capacitor connected in parallel is 2.0μF 3.0μF 4.5μF 9.0μF 42. A cell of e.m.f. 1.5 V and internal resistance 1.0Ω is connected to two resistors of resistances 2.0Ω and 3.0Ω in series. Calculate the current through the resistors 0.25 A 0.30 A 0.35 A 0.50 A 43. An electric lamp rated 120 W is used on a 240 Vrms, calculate the resistance of its filament. 480Ω 360Ω 60Ω 2Ω 44. Which of the following statements about a bar magnet is correct? Iron fillings cling uniformly along the length of the bar magnet The magnet properties are more pronounced at the middle of a magnet It is impossible to have the same poles at the end of a magnet The magnetic properties are pronounced at points near the ends of the bar 45. The force experienced by a current-carrying conductor moving in a magnetic field is employed in the working of the Moving coil ammeter Electric bell Electric motor Which of the statements above are correct? I and II only II and III only I and III only I, II and III 46. The breaking up of an atomic nucleus into two fragments of nearly equal sizes is known as Nuclear fusion Nuclear fission Thermonuclear reaction Natural radioactivity 47. A 500 kV is applied across an X-ray tube. Calculate the maximum velocity of the electrons produced. [Me =9.1×10-31kg, e = 1.6×10-19 C] 4.2×108ms-1 1.8×108 ms-1 4.2×105ms-1 1.8×105ms-1 48. A radioactive substance of mass 768 g has a half-life of 3 years. After how many years does this substance leave only 6 g undecayed? 21 18 15 12 49. Fusion is not usually used for generating electric power because No energy is released when fusion takes place Very high temperatures are required to initiate fusion reaction The raw materials needed are not easily available Heavy nuclei are involved 50. An atom (_91^234)P emits a gamma radiation. The resultant nuclide is (_90^234)Th (_889^234)Ac (_90^230)Th (_91^234)Pa

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